254 /•.'. S. Larsen, Jr., and W. T. Schaller — 



Chemical Composition. 



(W. T. SCHAI.I.ER.) 



The now mineral is infusible, becomes blue when heated 

 with cobalt nitrate, and gives a lend reaction when fused with 

 sodium carbonate on charcoal. A little water is given off when 

 it is heated in a closed tube. It is practically insoluble in acids. 



After the qualitative analysis had shown what the essential 

 components of the mineral were, a preliminary quantitative 

 analysis was made, the approximately correct results not being 

 here given. With a knowledge of the composition and the 

 experience gained in making the preliminary analyses, the 

 chemical composition of hinsdalite was determined on carefully 

 selected and pure material. The results obtained, together 

 with the ratios deduced therefrom, are shown below. 



Analysis and ratios of hinsdalite. 



PbO 31-75 -142 ) .,__ . n . 



SrO. 3-11 -030 | {12 1-93 or 2 



CaO — trace 



A1,0 3 .- 20-47 -260 2-92or3 



S0 3 14-13 -177 199 or 2 



P 2 6 14-50 -102 P14 or 1 



H,0 10-25 -570 6-40 or 6 (=6 X 1-07) 



100-21 



The ratios agree well with the formula, 2Pb0.3Al,0 3 .2S0 3 . 

 P,0 6 .6H. 2 0, except that the P 2 6 and H 2 are a little high. 

 A comparison of the analysis with the calculated percentages is 

 shown below. The sample analyzed consists of 82 - 56 per cent 

 of 2Pb0.3Al,0 3 .2S0 3 .P 2 5 .6H.,0, and 1744 per cent of 2SrO. 

 3A1 2 3 .2S0 3 .PA.6H 2 (svanbergite). 



Under 1 is given, in the table below, the analysis of the 

 Colorado mineral ; under 2, the calculated composition of 

 2Pb0.3Al 2 3 .2S0 3 .P 2 6 .6H 2 ; under 3, the composition cal- 

 culated for a mixture of 82-56 per cent of the pure lead 

 mineral and 17-44 per cent of the pure strontium mineral 

 (svanbergite) ; and under 4, for comparison, the calculated 

 composition of pure svanbergite. 



Comparison of analysis with calculated composition. 



12 3 4 



PbO... 31-75 38-37 31-68 



SrO 3-11 3-91 22-43 



A1 2 3 26-47 26-36 27"55 33-19 



S0 3 14-13 13-77 14-39 1732 



P 2 O r 14-50 12-21 12-76 15-37 



H 2 0" - 10-25 9-29 9-71 11-69 



100-21 100-00 100-00 100-00 



